1. Field of the Invention
The invention relates to a pipeline-type serial multiplier circuit having a cellular structure for multiplying two synchronized streams of digital data, that is to say a stream A consisting of n bits [a.sub.n . . . a.sub.k . . . a.sub.1 ] and a stream B consisting of p bits [b.sub.p . . . b.sub.k . . . b.sub.1 ], where n, k and p are integers, by forming in each cell of the structure, in the pipeline mode, the partial products of the multiplicand A and each bit of the multiplier B, after which they are successively added at a clock frequency F, each cell of the order k comprising:
an elementary one-bit adder which receives the data x.sub.k, y.sub.k and the carries c.sub.k, and which at a given instant outputs a result v.sub.k and a carry c.sub.ok, so that EQU v.sub.k =(x.sub.k & y.sub.k & c.sub.k) modulo 2 EQU c.sub.ok =(x.sub.k & y.sub.k & c.sub.k)/2,
where c.sub.k is at a given instant equal to the data c.sub.ok determined in the same cell during the previous clock period, after which it is delayed so that c.sub.k =c.sub.ok (d),
delay means for synchronizing the data delivered by two successive cells, and
means for the temporary storage of a data bit and the carry c.sub.ok.
For performing the serial multiplication of two digital data, each bit of one of the data is stored in the cells of a multiplier circuit; these bits are multiplied by the bits of the second data in order to produce partial products which are added according to their binary weight.
2. Related Art
A multiplier circuit of this kind is known from GB No. 2 166 272A which describes a serial multiplier circuit which operates on signed data and which, using an external flag, renders the multiplier circuit cascadable when the number of bits of the input data is to be extended.
However, the cited document describes only the execution of truncated multiplications: only the most-significant part of the result is delivered. The result, therefore, is an approximation. Thus, a first problem to be solved for given applications consists in that the exact result of the operation must become available, however, without increasing the calculation time.